If you remove one from eleven, it becomes ten. If you remove one from nine, it becomes ten.

How is this possible?

There are people and strange monkeys on this island, and you can not tell who is who (Edit: until you understand what they said - see below). They speak either only the truth or only lies.
Who are the following two guys?
A: B is a lying monkey. I am human.
B: A is telling the truth.

How old is your son? asked a man to his neighbour. My son is five times as old as my daughter and my wife is five times as old as my son. I am twice as old as my wife whereas my grandmother, who is celebrating her eighty-first birthday is as old as all of us put together.

How old is the man's son ?

Can you identify the Oscar-winning movie from the rebus below?

We have four gears with below features=> Both Gear A and D has 60 teeth=> Gear B has 40 teeth=> Gear C has 20 teeth=> Every two minutes, Gear B makes 25 full turns.What is the relative speed of Gear A and Gear B?

Begin with a word, five letters to my name,
Remove the first and last but I am the same
Take out my middle and still, I remain.
What word am I?

Identify the hidden meaning behind this picture?

The following sentence is false. The preceding sentence is true.
Are these two sentences true or false?

How many triangles are there on the puzzle below?

There are are five things wrong with this sentence; only geniuses will be able to to spot all of the mitstakes